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Trust Access Disable For VBApplications — Sigma Rule

Sigma rule 1a5c46e9-f32f-42f7-b2bc-6e9084db7fbf. Trust Access Disable For VBApplications — Sigma Rule. Detects registry changes to Microsoft Office "AccessVBOM" to a value of "1" which disables trust access for VBA on the victim machine and lets attackers execute malicious macros without any Microsoft Office warnings.

Rule metadata and linked tags

Author: Trent Liffick (@tliffick), Nasreddine Bencherchali (Nextron Systems). Source status: test; severity: high. Source dates: 2020-05-22 / 2023-08-17.

{
  "category": "registry_set",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 90810ac623d402354f1f0f5a5f25d67215fbcfea58c7425dc87fe18e6da345fe

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Trust Access Disable For VBApplications
id: 1a5c46e9-f32f-42f7-b2bc-6e9084db7fbf
related:
    - id: 9b894e57-033f-46cf-b7fa-a52804181973
      type: obsolete
status: test
description: Detects registry changes to Microsoft Office "AccessVBOM" to a value of "1" which disables trust access for VBA on the victim machine and lets attackers execute malicious macros without any Microsoft Office warnings.
references:
    - https://twitter.com/inversecos/status/1494174785621819397
    - https://www.mcafee.com/blogs/other-blogs/mcafee-labs/zloader-with-a-new-infection-technique/
    - https://securelist.com/scarcruft-surveilling-north-korean-defectors-and-human-rights-activists/105074/
author: Trent Liffick (@tliffick), Nasreddine Bencherchali (Nextron Systems)
date: 2020-05-22
modified: 2023-08-17
tags:
    - attack.persistence
    - attack.defense-impairment
    - attack.t1112
logsource:
    category: registry_set
    product: windows
detection:
    selection:
        TargetObject|endswith: '\Security\AccessVBOM'
        Details: 'DWORD (0x00000001)'
    condition: selection
falsepositives:
    - Unlikely
level: high

Original YAML and metadata in JSON

False positives

  • Unlikely

Source references

Connected ecosystem references

Exact source-tagged techniques

Telemetry review

Read the original logsource above, then inspect the linked detection workspaces for technique-level sensor context. No per-rule telemetry equivalence is inferred.

Pinned research references. No browser attack runner, live simulation result or validated detector is asserted. Source mappings and validation limits are preserved. ATT&CK / Atomic provenance · Detection provenance.